Iranian Journal of Physics Research
Year:2006 | Volume:6 | Issue:1|Papers Count:10

Cd0.96Zn0.04Te crystals were grown using vapor phase gas transport method (VPGT). The results show that dendritic crystals with grain size up to 3.5 mm can be grown with this technique. X-ray diffraction and Laue back-reflection patterns show that dendritic crystals are single-phase, whose single crystal grains are randomly oriented with respect to the gas-transport axis. Electrical measurements, carried out using Van der Pauw method, show that the as-grown crystals have resistivity of about 104 Ω cm and n-type conductivity.

A systematic study of the intergranular properties of (Bi,Pb)2 Sr2Ca2CU3Oy (Bi2223) polycrystalline samples has been done using the electrical resistivity and AC susceptibility techniques. In this study, we have prepared a series of Bi2223 samples with different sintering temperatures. The XRD results show that by increasing the sintering temperature up to 865°C, the Bi2212 phase fraction decreases. It was found that the Bi2212 phase on the grain boundaries is likely to play the role of the weak links and consequently reduces the intergranular critical current densities.

In this paper, the electron localization length was calculated numerically in a one-dimensional chain of atoms with random binary alloy. It is shown that in a one-dimensional finite-size chain of atoms, the localization length of the electron wave function decreases with increasing impurity concentration and with more increasing of the impurity concentration, the localization length becomes smaller than the system size and therefore insulator-metal transition occurs.  

We study processes in which neutrinos can be generated as a possible source for the neutron emission form neutron stars. In the high energy limit and in the range em < E < Mw the cross sention for ge →ev`v is analytically calculated. We also calculate the cross section for gg→v`v in the noncommutative space. The obtained results in comparison with the cross section for gg→v`v and gg→gv`v in the commutative space could be quite important in the astrophysics. As a result the cross section for gg→v`v in the noncommutative spaces, in the range A = 100- 300Ge V, is comparable with its counterpart in the commutative space.  

Variation of electrical resistivity of Bismuth nanowire versus magnetic field and temperature are considered. We study the size effect and surface scattering of the carrier in thin wire for systems with ellipsoidal Fermi surfaces. Results are in good agreement with experimental points.

Nolen-Schiffer Anomaly in mirror nuclei due to the NN interactions with isospin mixing between T=0 and T=1 mesons of the same spin and parity are investigated. With the computation of coulomb energy along with the charge symmetry breaking (CSB) effects provide a reasonably accurate description of binding energy differences between 39Ca-39K, 41Sc-41Ca mirror nuclei.

We have studied a practical approach for the inclusion of non-isotropic impurities in the systems showing integer quantum Hall effect. We observe that if the impurity distribution in the direction which the electric field applies, then the localized levels goes out from the origin with respect to the isotropic case, and the Hall step will the clearly observed.  

In this paper the Klein-Gordon and the Dirac Oscillators in a non-commutative space and in a constant magnetic field are investigated. It is shown that for a specific value of the magnetic field, one may map these oscillators from a noncommutative space to a commutative space.

Phase formation of manganese ferrite prepared by co-precipitation method is studied at different annealing temperatures. It is shown that the spinel phase is formed by quenching only in inert gas. XRD patterns show that the background picks fall in intensity by increasing annealing temperature and the single phase is achieved by magnetic separation.